Narcissism is a spectrum; everybody's a little narcissistic, and it changes over time. All kids are VERY narcissistic early on, most grow out of it as they experience unconditional love from their parents and are allowed to be their authentic selves in various social contexts.

For various reasons - some kids don't. Bullying can certainly contribute.

So they develop maladaptive strategies (which can look like the first few "stages" in this article) and have to undo the damage later in life (which can look like the later "stages" from the article) to have a chance to experience real human connection.

I think the article can be very beneficial for people who struggle with this, even if it doesn't explicitly mention what the technical name of the struggle is (and BTW it does not have to be NPD - there might be other reasons for people to have similar problems). Maybe even BECAUSE it doesn't mention narcissism (cause narcissism is currently villified on the social media as "they are actual demons that cannot be saved" - so people are very wary of identifying with it, which makes it less likely they will work on themselves).

BTW I'm very disappointed in the current fad on social media of villifying one mental health issue after another only to then come to realize "oh wait, they're actually people not monsters". I've seen it with BPD, now it's the NPD turn. It's usually done for ugly reasons, too (somebody hurt by a person with $mental_health_problem search for validation, so influencers jump in with feel-good validation that portrays the other side as demons).